Electric bell.



No. 801,035. PATENTED 00T. s, 1905..

W. J. MURDOCK.

ELECTRIC BELL. APPLIGATION FILED JULY 21, 1904.

WILLIAM J. MURDOOK, OF BOSTON, MASSACHUSETTS.

ELECTRIC BELL.

Specification of Letters Patent.

Patented Oct. 3, 1905.

Application led July 2l, 1904, Serial No. 217,566.

To @ZZ iff/1,0771, it 71u07/ concern:

Be it known that I, VILLIAM J. MURDooK, of Boston, in the county of Suffolk and State of l\fIassachusetts, have invented certain new and useful Improvements in Electric Bells, of which the following is a specification.

This invention relates to magneto-electric bells, and has for its object to provide a simple, durable, and relatively inexpensive construction of a bell of this class.

The invention consists in the improvements, which I will now proceed to describe and claim.

Of the accompanying' drawings, forming a part of this specification, Figure 1 represents a top plan view of an electric bell embodying my invention, the gong being removed. Fig. 2 represen ts aside elevation of the same, showing the gong in dotted lines. Fig. 3 represents a section on line 3 3 of Fig. 1. Fig. 4 represents a section on line 4 4 of Fig. 1. Fig. 5 represents a section on line 5 5 of Fig. 1. Fig. 6 represents a plan view of the electromagnet removed from the base or holder. Fig. 7 represents an end view of the electromagnet.

The same reference characters indicate the same parts in all the figures.

My improved bell comprises an electromagnet having the usual pole-pieces l() 10 and coils 11 11, the said parts being connected by suitable end pieces or heads 12 12.

13 represents a base or holder, of suitable insulating material, adapted to be formed or molded upon the magnet. In forming the base 13 the plastic material of which it is composed is molded in such manner as to practically envelop the magnet, the completed base having integral parts which bear upon the magnet on all sides of the same in such manner as to prevent displacement or loose independent movement of the magnet in any direction. The base is provided with a recess 14, which extends across one end of the magnet, the poles of the magnet being exposed at one side of said recess. The armature 15 of the electromagnet is located in the recess 14, the latter being formed to permit the oscillation of the armature under the influence of the magnet and a suitable retracting-spring which forces the armature away from the poles of the magnet. The armature is pivoted at one end upon a stud or post 16, which is suitably secured to the base.

It will be seen that by embedding the electromagnet in a base or holder of insulating material adapted to be molded and by providing said base with a magnet-receiving recess at one side of which the poles of the magnet are exposed I provide a construction 6o which insures the secure retention of the magnet in its proper position and locates the magnet below the upper surface of the base, so that the open space under the gong 18, which is mounted upon the base, as hereinafter described, is reduced to the minimum. Liability of obstruction of the moving parts by accumulations of insects, &c., in said space is therefore materially reduced.

The end pieces 12 12 of the electromagnet 7o are provided with oppositely-projecting ears` 19 19, having oritices for the reception of the screws which attach the base to the support of the bell. In the base are molded or otherwise formed orifices 2O 21, coinciding with 75 the orifices in the ears 19 for the accommodation of the attaching-screws. The orifices 20 are of greater diameter than the screwreceiving orifices in the ears 19. Hence said ears serve as bearings or washers for the at- 8o taching-screws, the ears being rigidly afiixed to the magnet, which in turn is firmly embedded in the base, so that the ears occupy the desired predetermined positions and serve to reinforce the more or less brittle material of the base. The stud or pin 16, on which the armature is pivoted, is afiixed to an ear 22, formed on one of the end pieces 12, so that said pin occupies the desired predetermined position relatively to the magnet. 9o

23 represents the hammer or striker, which is afxed to a shank 24, the latter being pivoted upon a stud 25, suitably secured to the base. An arm or extension 26 of said shank enters a slot 27 in the swinging end of the ar- 95 mature, so that the hammer is vibrated by the armature. The spring which retracts the armature may be a spiral spring 28, mounted on the stud 25 and acting through the arm 26 on the armature. The hammer-shank 24 is 10o inclined upwardly, as indicated in Fig. 2, so that the hammer is located above the base in position to act on the gong. The base is provided with a recess 30, which receives the lower portion of the hammer-shank and opens into the armature-receiving recess 14.

32 33 represent the binding-screws, which secure the usual circuit-wires 34 35, said screws being suitably engaged with the base. rlhe wire 34 is connected with the armature through 3T 37 represent orilices formed in the base,

through which portions of the wires 34 and 35 pass.

38 represents a standard which is integral with the base and projects upwardly therefrom, and 39 represents a screw-threaded stud engaged with the standard, the plastic material ot' the standard being preferably molded upon the stud. The gong 18 is supported by the standard and secured by the stud 39 and a nut 40, engaged with the upper end oi' said stud, as indicated in Fig. 3.

From what has been said it will be observed that the current passing from its source reaches the magnet through wire 35 and returns to the said source otl supply through the armature l5, spring 36, and wire 34. When the circuit is closed,the armature l5 is attracted by the magnet, whereupon the circuitis broken with contact-spring 36 and the armature returned to its normal position by spring E28, the hammer or striker moving in unison with said armature. As long as the circuit between the magnet and the source of supply is maintained the armature will vibrate back andforth in a manner well known in the operation ot electric bells.

I clairn-w l. An electric bell comprising an electromagnet, a base of insulating material molded around said magnet and containing a recess into which the poles of said magnet project7 Yand an armature located in said recess and free to oscillate therein.

2. An electric bell comprising a base of insulating material provided With orifices for the reception of attaching-screws, an electromagnet embedded within said base and provided with ears having perforations coinciding with said orilices, and an armature, said base being provided with a recess in which said armature is mounted and into which the poles of said magnet project.

3. An electric bell comprising an electromagnetv a base of insulating material molded around said magnet, and a screw-thread ed stud around which said base is also molded, said stud projecting above said base.

In testimony whereof I have aiiixed my signature in presence of two witnesses.

WlLLlAM J. MURDOCK.

fitnessesz C. F. BROWN, E. BATCHELDER. 

